On July 24, 1949 the great Wallace W. Atwood died at the age of 76. As a geographer and geologist, Atwood wrote and contributed to textbooks, taught classes, and even contributed to the New Jersey Geological Survey and the Wisconsin Natural History Survey. Although you may not immediately recognize his name, he contributed an important exhibit to the history of the Chicago Academy of Sciences and one of our fellow Chicago museums.

The Atwood Sphere in 1913 (Photo from Popular Science)

The Atwood Celestial Sphere opened at the Academy in June of 1913. What set it apart from other planetariums of the period was its ability to rotate around visitors as they stood inside it. Atwood, who served on the Academy’s Board and briefly as Acting Director of the museum, designed the incredible apparatus and it helped usher in a new age of planetariums.

Illustration of the Atwood Sphere (From Popular Science)

The sphere was constructed of a thin galvanized sheet metal and only measured 15 feet in diameter. Tiny perforations in the exterior of the sphere allowed light to penetrate, appearing as stars to those viewing from the inside. Atwood designed the celestial sphere to portray the stellar sky as seen from Chicago and visitors would watch as the sun, moon, and stars rotated around them in simulation of Earth’s orbit through the solar system. The sphere was utilized heavily for educational programs at the Academy. School groups, clubs, and other visitors would tour the sphere, with programs often led by Atwood himself during his time with the Academy.

The Sphere as it looked in the Laflin Memorial Building in 1987

When the Academy began extensive redesign of its exhibits and developing life zone dioramas in the 1960s, the exterior of the Sphere was painted to look like the Earth and the ceiling of the Laflin Building painted to look like the night sky to blend more readily with the new exhibits. When the Academy moved from the Laflin Building in 1995, the Sphere was transferred to the Adler Planetarium, officially making the move on December 16, 1997. Once it was transferred the staff at the Adler began to restore it to its original 1913 appearance. The geographical features that had been built up on the Sphere’s exterior were flattened, paint was removed and the original star holes were cleaned. Instead of walking into the Sphere, visitors now enter the Sphere in a motorized cart, and the Sphere rotates around the cart, but the experience is very similar to what Academy visitors experience when they walked into the Sphere in 1913.

The Atwood Sphere as it looks today on exhibit at the Adler Planetarium

In June 1913, the Chicago Academy of Sciences presented an exhibit to its visitors unlike any other. It was a planetarium where, unlike others of the time period, visitors could walk inside to experience the night sky while the apparatus rotated around them.

The Atwood Celestial Sphere was designed by and named for Wallace W. Atwood, who served on the Academy’s Board and briefly as Acting Director of the museum. Mr. LaVerne W. Noyes, President of the Board of Trustees, had the structure crafted by his company, Aermotor Windmill Company, and donated it to the Academy.

Wallace W. Atwood inside the Atwood Celestial Sphere

Atwood Celestial Sphere, c1913

The sphere, constructed of a thin galvanized sheet metal, was only 15 feet in diameter. Tiny perforations in the exterior of the sphere allowed light to penetrate, appearing as stars to those viewing from the inside. Atwood designed the celestial sphere to portray the stellar sky as seen from Chicago and visitors would watch as the sun, moon, and stars rotated around them in simulation of Earth’s orbit through the solar system. The sphere was utilized heavily for educational programs at the Academy. School groups, clubs, and other visitors would tour the sphere, with programs often led by Atwood himself during his time with the Academy.

Wallace W. Atwood with children inside the Celestial Sphere

The stars were positioned with such mathematical precision that in 1941, the U.S. Navy began incorporating use of the Atwood Sphere in navigational training exercises for the U.S. Naval Reserve Unit stationed on the Chicago Campus of Northwestern University. Modifications were made to the Sphere to accommodate these trainings, including the installation of a meridian (an arc that follows the circumference of the sphere and passed through the zenith) and movable arm with which to measure the zenith angle – the distance between the zenith (the point directly overhead) and any star.

In the 1960s, the Academy began extensive redesign of its exhibits and developing life zone dioramas created by William Beecher and Academy staff. The exterior of the Atwood Celestial Sphere was painted to look like the Earth and the ceiling of the Laflin Building painted to look like the night sky to blend more readily with the new exhibits.

Thurston Wright working on the Atwood Celestial Sphere, c1950s

Atwood Celestial Sphere with the exterior painted to look like Earth, c1960s. William Beecher in the foreground and Thurston Wright in the background.

The Atwood Celestial Sphere was transferred to the Adler Planetarium in 1995 when the Academy vacated its Laflin Building, where it currently resides.